The Structure and Pattern of Urban Network in the Lanzhou-Xining Urban Agglomeration

In this paper, we use factor analysis to evaluate the urban comprehensive quality of each city in the Lanzhou-Xining (Lan-Xi) urban agglomeration. The time distance was obtained by using GIS spatial analysis, and the structure and pattern of the spatial network were analyzed by using the gravity model and social network analysis method. The results show that: 1) The scale effect of the Lan-Xi urban agglomeration is gradually emerging, and it is gradually forming the urban agglomeration with Lanzhou and Xining as the core, the Lan-Xi high-speed railway as the axis, and a high-dense connection. 2) Lanzhou and Xining are at the core of the Lan-Xi urban agglomeration, which has a strong attraction and spreads to neighboring cities. 3) In the network structure of the Lan-Xi urban agglomeration, Lanzhou, Baiyin, Gaolan, Yuzhong, Yongdeng, Dingxi, Lintao, Xining, Ledu, Huangzhong, Ping'an, Minhe and Datong are located in the network core position, which have the superiority position and lead to the entire regional communication enhancement and the regional integration development. 4) This urban agglomeration has significant subgroups, eight tertiary subgroups and four secondary subgroup; the tertiary subgroups which compose secondary subgroup have a close connection and mutually influence each other. 5) The Lanzhou Metropolitan Area and the Xining Metropolitan Area have an important impact on the surrounding cities, and the peripheral cities are basically controlled by the central city. The Dingxi subgroup, Lintao-Linxia subgroup, Gonghe subgroup have more structural holes than the subgroups within the Lanzhou Metropolitan Area and the Xining Metropolitan Area, so the peripheral cities of these subgroups have relatively less connection with surrounding cities.